Sid and Marty Krofft sure had active imaginations. In a span of a few years, the brothers created some of the surreal children's programming in television history. It began with The Banana Splits for Hanna-Barbera in 1968, but the two stepped out on their own a year later with H.R. Pufnstuf. The similarly minded series The Bugaloos, Lidsville, Sigmund and the Sea Monsters, and Land of the Lost followed.

But H.R. Pufnstuf set the mold, with its youthful protagonist, floppy costumed creatures, and psychedelic fantasy. Jimmy (Jack Wild) was the hero, aided by the titular star H.R. Pufnstuf, a bulbous dragon. But every story needs a villain. Enter Wilhelmina W. Witchiepoo.

With her iconic cackle, Witchiepoo is undoubtedly implanted in the memory of any kid who grew up in the era. Billie Hayes, a Broadway veteran, portrayed the witch. She became such an icon (in a shockingly short amount of time — Pufnstuf only aired for 17 episode) that Hayes essentially played iterations of the same character on other shows. See the Bewitched episode "Hansel and Gretel in Samantha-Land," for example. She was also Weenie the Genie in Lidsville.

Those of an older generation might remember her better as Mammy Yokum, the scrappy matriarch of Li'l Abner. Hayes played the character, which was born in the popular newspaper comic strips, both on stage and in the 1959 film. Here she is in character.

The Everett Collection

Born and raised in Illinois, Hayes continued to work in children's television for decades, into her 90s, as recently as 2016, when she voiced a character on Transformers: Rescue Bots. On April 29, she died of natural causes, according to The Hollywood Reporter. She was 96.

Sid and Marty Krofft — still working in television to this day — honored her on Twitter with this touching tweet.